Arteriovenous Fistula (AVF)
Arteriovenous fistula (AVF) are connections between an artery and vein created surgically, and are most often placed in the forearm or upper arm. AVF are considered ideal for dialysis, as they take advantage of the body’s own blood vessels and do not involve placement of any foreign material in the body. In addition, AVF allow for high blood flow rates, which can be thought of as the rapid exchange of blood in and out of the body during dialysis. Blood flow rates are the determining factor for how quickly dialysis can be performed, and is highest in AVF, followed by arteriovenous grafts (AVG) and finally dialysis catheters.
Once surgically created all AVF undergo a process called maturation, a period of weeks to months where the vein connected the artery grows in size and allows high blood flow rates for dialysis. While most AVF mature on its own, there are sometimes problems that arise that won’t allow the vein to increase in size and makes dialysis difficult or impossible. In these instances, the AVF requires evaluation and often interventions to assist maturation.
In order to assist the AVF mature, one or two catheters are placed into the AVF in order to inject contrast dye and evaluate the AVF. The entire AVF is evaluated, from the artery all the way through the end of vein, as well as all the connecting veins that drain into the heart.
Most often, a stenosis (narrowing) is identified in either the vein or artery that is blocking blood from flowing freely through the AVF. These stenosis can be treated with balloon angioplasty, a process where a balloon is temporally inserted through the catheter and inflated inside the blood vessel, opening up the narrowing in the blood vessel and allowing blood to flow rapidly though the AVF.
Other times, there no distinct narrowing but instead the entire vein remains small, too small for needles to be inserted for dialysis. In these cases, a balloon can be used to temporarily stretch the entire vein. This process allows the vein to expand and accept more blood from the artery, and subsequently grow in size so that is can be used for dialysis.
Rarely, the artery is connected to a vein that has multiple connections to other veins. These multiple connections decrease the pressure, and the decrease pressure causes the AVF to remain small and unusable for dialysis. Therefore, the connections to other veins must be addressed. A catheter is used to find the small connection to the other veins and the connections are blocked during a process called embolization. Small metal coils are placed through the catheter and go inside the connecting veins. This blocks the blood flow to the other veins, and forces the blood to flow through the AVF. The higher blood flow and pressure then cause the AVF to mature and become suitable for dialysis.
AVF maturation procedures often last 30-45 minutes, and are performed while patients are awake but sedated. Medicines are given to make patients comfortable and reduce pain, and patients are able to go home 30-45 minutes after the procedure. During the recovery period patients are allowed to rest, visit with family members, watch TV, or enjoy complimentary food and beverage. Because the medications given during the procedure preclude patients from driving after the procedure, complimentary transportation to and from Midwest Vascular Access is provided.